92 HORSETAILS AND CLUB MOSSES 



but it finally becomes independent when it has produced a 

 rhizome, roots, stems and leaves to form the sporophyte 

 with which we are familiar. 



SUMMARY. 



Alternation of Generations occur. 



Gametophyte. The gametophyte is greatly reduced; there 

 are male gametophytes which produce only antheridia, 

 and female gametophytes which produce only archegonia. 

 The male gametophyte is a branched prothallium which 

 bears one or more laterally placed rounded antheridia filled 

 with coiled sperm cells. The female gametophyte, which is 

 larger than the male gametophyte, forms one or more arche- 

 gonia, similar to the archegonia of the ferns. 



Sporophyte. The sporophyte is the conspicuous stage. 

 Like the fern it has roots, stems and leaves. 



Roots. The roots develop from the endodermal layer of 

 the rhizome; secondary roots arise from the endodermis of 

 the older roots; all are covered with root hairs; they are brown 

 or black and very tough and fibrous. 



Stems. The stems are jointed and the internodes are 

 furrowed. They contain the assimilative tissue and stomata 

 occur in the furrows of the internode. The spore-bearing 

 cones are borne at the end of the stem, and are made up of 

 spirally arranged sporophylls which bear the sporangia con- 

 taining the spores. 



Leaves. The leaves are reduced to scales, and they are 

 arranged in the form of whorls at the nodes of the stem and 

 branches. 



CLUB MOSSES (LYCOPODIALES) 



Lycopodium grows in dry or moist soil. 



There is a great variation in the sporophyte of the different 



